﻿// Jinx AJAX Framework
// Copyright (C) 2008 Blake Hegerle
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

namespace Formality.FormalSystem.Parser
{
    public static class Binder
    {
        public static Proposition Bind(this Proposition P)
        {
            return P.Bind(new Bindings());
        }

        public static Proposition Bind(this Proposition p, Bindings Bindings)
        {
            if (p.Type == PropType.Binder)
                foreach (var v in p.Variables)
                    Bindings.Bind(v);

            p = new Proposition(
                p,
                v => new Variable(v.Name, Bindings[v.Name]),
                o => Bind(o, Bindings)
                );

            if (p.Type == PropType.Binder)
                foreach (var v in p.Variables)
                    Bindings.Unbind(v);

            return p;
        }
    }
}